Answer:
(a) 
(b) P = 0.816 Watt
Explanation:
(a)
The power radiated from a black body is given by Stefan Boltzman Law:

where,
P = Energy Radiated per Second = ?
σ = stefan boltzman constant = 5.67 x 10⁻⁸ W/m².K⁴
T = Absolute Temperature
So the ratio of power at 250 K to the power at 2000 K is given as:

(b)
Now, for 90% radiator blackbody at 2000 K:

<u>P = 0.816 Watt</u>
In order to find total magnification of a microscope, you need to multiply the power of eyepiece and objective lens.
Hope this helps!
Answer:

Explanation:
Density can be found by dividing the mass by the volume.

The mass of the quartz is 30 grams and the volume is 6 cubic centimeters.

Substitute the values into the formula.

Divide.

The density of this piece of quartz is 5 grams per cubic centimeter.
The answer is 165.3 cm³.
P1 * V1 / T1 = P2 * V2 / T2
The initial sample:
P1 = 84.6 kPa
V1 = 215 cm³
T1 = 23.5°C = 23.5 + 273 K = 296.5 K
At STP:
P2 = 101.3 kPa
V2 = ?
T2 = 273 K
Therefore:
84.6 * 215 / 296.5 = 101.3 * V2 / 273
61.34 = 101.3 * V2 / 273
V2 = 61.34 * 273 / 101.3
V2 = 165.3 cm³
Answer:Weight is the result of gravity . The gravitational field strength of Earth is 10 N/kg (ten newtons per kilogram). This means an object with a mass of 1 kg would be attracted towards the centre of Earth by a force of 10 N. We feel forces like this as weight.
Explanation: